HoTT code cleanup.
Adding unit test for some gps conversion code to demystify it.
Updating Development docs.
Updating documentation.
Updated GPS logitude/latitude calculation.

The existing implementation that was ported over was trying to work with
different values.  By writing a unit test for the code that stores
values in GPS_coord it was possible to have known values which could
then also be used to write a unit test for the HoTT telemetry which
finally enabled production code to be written.

Hopefully it will work, unable to test further since my GPS unit is
playing up.